Grain-door table clamp



Mar. 6, 1923.

w. W. JACKSON GRAIN DOOR TABLE CLAMP Filed June 6, '1922 w w 2 f Patented Mar. 6, 1923.

times WILLIAM w. JACKSON, or OAKDAALE, LOUISIANA, AssIoNoR r MUMMERT LUMBER & TIE COMPANY, or CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

GRAIN-DOOR TABLE CLAMP.

Application filed June 6,

To all who-m it may concern:

Be it known that I, WILLIAM IV. JACKSON,

a citizen of the United States. and a resident of Oakdale, in the parish of Allen and State of Louisiana, have invented certain new and useful Improvements in Grain-Door Table Clamps, of which the following is a specihcation. 1 I

"My invention is concerned with graindoor table clamps, and is designed to produce a clamping device of the class de scribed in which the operators at each end of the table, bydepressing-their respective treadles, can produce a. powerful horizontal thrust on the surface of thetable-to hold the boards tightly together while the battens are being nailed on, thus insuring that the completed door shall be perfectly tight.

To illustrate my invention, I annex hereto a sheet of drawings, in which the same reference characters are used to designate identical parts in all the figures, of which,

Fig. 1 is a perspective view of a table embodying my invention, with the parts in their non-clamping position;

Fig. 2 is an end elevation ofthe same with the treadles depressed to operate the clamp; and

F ig. 3 is a plan view in section on the line 3 3 of Fig. 2. r

In carrying out my invention, I employ the customary table 10 having the four legs 11 and the working top surface 12, which is preferably covered witlimetal, and has on the front side thereof the clamping rail 13 and on one end the transverse abutment 14 against which the ends of the boardsl 15, indicated in dotted lines in Fig. 1, are

placed. The mechanism thus far described is of a customary construction and need not be explained in greater detail.

Pivoted at both ends of the table on the pins 16, or other suitable bearings, are the levers 1?, partially of a bell-crank shape, as shown, and having the upturned ends 18 of the load arm, to which ends are rigidly secured the longitudinal bar 19, which normally stands away from the adjacent edge of the table a few degrees. Hinged on the bar 19 by the hinges 20 is the movable clamping rail 21, which is preferably con- -structed of wood, and will have its outer edge parallel with the adjacent edge of the rail 13. The rail is a quadrilateral in cross section,-preferably with its under side 22 1922. Serial N0. 566,431.

out at such an angle to the other three sides, which are at right angles to each other, that when the parts are in the operative position shown in Fig. 1, the bottom 22 of the rail rests flat on the adjacent surface 12. At each end of the table, upon the pin 23, I fulcrum the treadle 24, which is a lever of the second class, and has pivoted thereto at 25 a link 26, which is connected to the joint 27 of a toggle composed of the bar 28 pivoted to the frame at 29' at one end, and of the thrust bar 30, the other end of which ispivoted at 31 to the bottom of the power arm of the lever 17. The parts 26, 28 and 30, as well as the lever 17, are preferably composed of flat metal bars,suitably shaped, and I preferably employ a pair of the bars 30 at each end, one on each side of the'lever 17, and the bars 26 and 28, in order to secure additional rigidity. I preferably secure on the legs of the table at each end the guardrails 32, between which and the adjacent leg the treadle 24L reciprocates, and to normally hold and return the parts to the inoperative position shown in Fig. 1, I secure at each end a helically-coiled contractile spring 33, one end of which is conveniently secured to the rod 32 while the other end is hooked into an aperture in the lever 17, as shown.

The operation of the complete device is as follows: Assuming that the boards 15 have been placed on the surface 12 with their ends abutting against the member 14, then the operator at each end steps on his treadle 24, depressing it substantially to the position shown in Fig. 2, and during its movement, the powerful leverage exerted by the connections slides the movable rail 21 toward the stationary rail 13 with a powerful thrust and squeezes the boards 15 tightly against each other, in which position they are held by the depressed treadles until the battens havebeen nailed on, after which the treadles are released and the door can be removed.

While I have shown and described my in vention as embodied in the form which I at present consider best adapted to carry out its purposes, it will be understood that it is capable of modifications, and that I do not desire to be limited in the interpretation of the following claims except as may be necessitated by the state of the prior art.

What I claim as new, and desire to secure by Letters Patent of the United States, is: 1. In a device of the class described, the

combination with a table having a stationaryv clamping abutment at the top of one side, of a horizontally movable abutment on the top of the other side, a vertically extending lever fulcrumed to each end of the table, said abutment being connected at its ends to the upper ends of the two levers, a treadle lever fulcrumed to each end of the table,

a pair of toggle links at each end pivoted at one end to the lower end of the vertical lever and at the other end to the frame, and a link at each end connected at its upper end to the toggle joint and'at. its lower end to- I fsaid abutment being connected at itsends to the upper ends of the two levers, a treadle lever fulcrumed to each end of the table,

a pair of toggle links at each end pivoted at one end to the lower endio'f the vertical lever and atthe other end tothe frame, and a link at each end connected at its upper end to the toggle joint and at its lower end to thetreadle lever, and a helically-coiled'contractile spring connected at one end to one ofthe vertical 1evers and at the other end to the frame. v

i 3. In adevice of the class described, the

combination with a table having a stationary clamping abutment at the'top of one side, of a horizontally movable abutmenton the top of the other side, a vertically extending lever fulcrumed toward the rear of the table, said abutment being connected to the upper end of the lever, a treadle lever fulcrumed at the bottom of the table, a pair of toggle links pivoted at one end to the lower end of the vertical lever and at the other end to the front of the frame, and a link connected at its upper end to the toggle joint and at its lower end to the treadle lever.

I. In a device of the class described, the V combinationwith a table having a stationary I clampingabutment at the top of one side, of a horizontallymovable abutment on the top of the other side, a parallel bar to which said movable abutment ishinged, a vertically. extending lever fulerumedtoeach end 7 I ofthe table, said bar being connected atits ends to the upper ends of the two levers, a treadle lever fulcrumed to each end of the table, a pair voftoggle links ateach end. pivoted atone end'to the lower end of the In witness whereof, I have hereunto set my handthis 26th day ofMay, 1922,

' i i WIL IAM W. JACKSQN. 

